[MARMAM] First record of XXY in marine mammals and intersex sequencing method: new publication

Laura Joan Feyrer laura.joan at gmail.com
Thu Sep 12 15:00:21 PDT 2019

On behalf of my co-authors I'm excited to announce our publication in the
Journal of Mammalogy which describes: (1) the first records of genetically
intersex cetaceans and (2) the sequencing method for determining XXY
chromosome condition in mammals.

Please contact Dr. Einfeldt (tony.einfeldt at gmail.com) for a PDF.

Einfeldt, A. Orbach, D., & Feyrer, L.J. A method for determining sex and
chromosome copy number: sex-by-sequencing reveals the first two species of
marine mammals with XXY chromosome condition, Journal of Mammalogy, gyz131,


Molecular assays of sex determination typically rely on qualitative
evaluation of sex-linked markers, which can lead to uncertainty when
results contradict morphological identifiers of sex. To investigate whether
disagreement between phenotypic and genotypic assays of sex could be
underpinned by variation in sex chromosome copy number, we developed a
quantitative genetic method to determine sex that is broadly applicable to
mammals with XY sex determination. We sequenced a region of the zinc-finger
gene ZF, which has fixed genetic differences between the X and Y
chromosomes, and screened 173 cetacean specimens for ZFX–ZFY haplotype
identity and read depth. Using a subset of 90 male specimens, we
demonstrate that haplotype read depth is an accurate estimator of
chromosome copy number. We identified three specimens representing two
different cetacean species that had external female morphological traits, Y
chromosome haplotypes, and ratios of ZFX:ZFY haplotypes that were above the
1:1 value expected for genetic males. These results provide the first
evidence of XXY aneuploidy in cetaceans. Investigation of the reproductive
tract of one specimen, a True’s beaked whale (Mesoplodon mirus), revealed
an intersex phenotype; despite having external characteristics typically
diagnostic for the female sex, a penis and testes were present. Our results
suggest that intersex phenotypes may be associated with XXY aneuploidy, and
that this phenomenon may be underestimated due to it not being detectable
by qualitative assays for determining sex.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.uvic.ca/pipermail/marmam/attachments/20190912/ee057c4c/attachment.html>

More information about the MARMAM mailing list